Tier 2 — strong

Clinical validation of C12FDG as a marker associated with senescence and osteoarthritic phenotypes

Hambright WS, Duke VR, Goff AD, Goff AW, Minas LT, Kloser H, Gao X, Huard C, Guo P, Lu A, Mitchell J, Mullen M, Su C, Tchkonia T, Espindola Netto JM, Robbins PD, Niedernhofer LJ, Kirkland JL, Bahney CS, Philippon M, Huard J
Aging Cell 2024 23(5):e14113

Bibliography

PubMed
PMID 38708778
PubMed Central
PMC11113632
DOI
10.1111/acel.14113
Funding
Supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS/NIH; UH3AR077748), the Department of Defense Office of Naval Research (N00014-19-C-2052), major philanthropic support from Mitch & Linda Hart and the Borgen Foundation, and an Orthopaedic Research and Education Foundation grant funded by the Aircast Foundation (TAF-21-059).
Competing interests
Hambright, Ravuri, Philippon and Huard declared inventorship on US PCT Application 16994356, “Methods for treating disease associated with senescence.” Bahney disclosed intellectual-property royalties from Iota Biosciences, Inc. for US Patent 041263 and an Associate Editor role at the Journal of Tissue Engineering and Regenerative Medicine.

Study snapshot

DesignHuman observational biomarker-validation cohort with cross-sectional healthy-versus-osteoarthritis comparisons and an exploratory longitudinal subgroup analysis of self-reported fisetin users.
ModelHealthy adults aged 18–85 and adults with mild-to-moderate osteoarthritis; peripheral blood mononuclear cells and enriched T cells assessed by flow cytometry, with serum biomarker profiling.
Sample266 healthy participants enrolled; 140 generally healthy adults included in the primary age/senescence analysis; 75 osteoarthritis patients enrolled; exploratory fisetin subgroup n=10.
InterventionNo randomised study intervention. In the exploratory subgroup, 10 participants self-reported taking fisetin 100 mg/day between study visits; participants taking other fisetin doses or other senotherapeutics were excluded from that analysis.
DurationHealthy cohort enrolled December 2019 to March 2022. Fisetin subgroup reported use for 58 ± 31 days between paired visits.
EndpointsC12FDG++ (bright) peripheral blood mononuclear cells and enriched T cells by flow cytometry; Correlations between C12FDG++ PBMCs, chronological age and circulating senescence/SASP-related biomarkers; Comparison of C12FDG++ PBMCs and T cells in healthy versus osteoarthritis participants; Longitudinal change in C12FDG++ PBMCs and serum biomarkers in the self-reported fisetin subgroup

What the study showed, in plain terms

This 2024 human study asked whether a fluorescent marker called C12FDG can be used to detect senescent-like immune cells in blood — and whether those cells track with age, osteoarthritis, and exposure to fisetin.

Across the larger cohort, the researchers found that the bright C12FDG++ fraction of peripheral blood mononuclear cells increased with chronological age and overlapped with several circulating biomarkers associated with aging and the senescence-associated secretory phenotype. People with mild-to-moderate osteoarthritis also had higher C12FDG++ PBMC and T-cell levels than healthy comparison participants.

The fisetin finding is intriguing but preliminary. Ten participants who independently reported taking 100 mg of fisetin per day were compared with their own earlier blood samples. After an average of roughly two months, their bright C12FDG++ PBMC percentage fell by an average of 27.2%, and several circulating biomarkers also decreased.

This is not proof that fisetin clears senescent cells in humans. The fisetin subgroup was tiny, self-selected, not randomised, and had no placebo control. The study is best read as early human biomarker evidence that supports — but does not establish — a senotherapeutic effect and as validation work for a possible blood-based senescence assay.

Key findings

  • C12FDG++ PBMCs correlated with chronological age: among 140 generally healthy adults, the percentage of bright C12FDG++ PBMCs showed a statistically significant positive association with age (r=0.1947, p=0.0114).
  • The bright C12FDG signal aligned with other senescence biology: C12FDG++ PBMCs correlated with several age- and SASP-related circulating biomarkers, including GDF-15, sclerostin, MMP-3 and others, and the bright fraction aligned more closely with CD87/uPAR staining than the dim C12FDG fraction.
  • Osteoarthritis was associated with a higher peripheral senescence signal: C12FDG++ PBMCs and T cells were significantly elevated in participants with mild-to-moderate osteoarthritis compared with healthy controls.
  • Exploratory fisetin subgroup showed a 27.2% mean fall in bright PBMCs: 10 participants who self-reported taking fisetin 100 mg/day for 58 ± 31 days had a mean 27.2% reduction in C12FDG++ PBMC percentage versus their own baseline (p=0.0020).
  • Multiple circulating biomarkers decreased after reported fisetin use: MMP-3, MMP-9, leptin, sclerostin, PDGF-AA, IL-6, IL-8, MCP-1, GDF-11 and GDF-15 were reported as significantly lower at follow-up in the exploratory subgroup.

What this study can and cannot tell us

  • The fisetin analysis was observational, not a randomised trial. Participants self-reported taking fisetin; there was no placebo group, treatment allocation, adherence verification, or blinded intervention comparison.
  • The fisetin subgroup was extremely small. Only 10 participants met the similar-dose and timing criteria, making the estimate vulnerable to regression to the mean, confounding, selection bias and chance.
  • Biomarker changes are not clinical outcomes. A fall in C12FDG++ PBMCs or SASP-related proteins does not by itself prove systemic senescent-cell clearance, improved function, slower aging, or disease modification.
  • C12FDG is a senescence-associated marker, not a uniquely specific senescence label. The authors present the bright fraction as more physiologically informative than the dim fraction, but further prospective validation and cell-specific immunophenotyping are needed.
  • Relevant intellectual-property interests were disclosed. Several authors declared inventorship on a patent application concerning treatment of diseases associated with senescence.

Related papers in the corpus

Tier 3
Fisetin as a senotherapeutic agent — evidence and perspectives for age-related diseases
Tavenier J et al. · Mechanisms of Ageing and Development · 2024
Tier 3
Fisetin is a senotherapeutic that extends health and lifespan
Yousefzadeh MJ et al. · EBioMedicine · 2018
Tier 2
Senolytic Drugs Attenuate Osteoarthritis-Related Articular Cartilage Degeneration: A Clinical Trial (NCT04210986)
Evans TA (Steadman Philippon Research Institute) et al. · ClinicalTrials.gov (trial registry record with posted results — not yet published as a peer-reviewed journal article) · 2024

Citation network

Articles citing this research paper

3 articles

Biohack Blueprint analyses that reference this study in their evidence base.

Editorial review

Reviewed by the Biohack Blueprint research team

Last verified

Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction Dr. Amr Yasser, PhDCardiometabolic, Musculoskeletal, Gut & Bioavailability Dr. Abdulla Mostafa, PhDCellular Senescence, Neurological, Mitochondrial & Brain-Ageing Biology